Visceral leishmaniasis in a rheumatoid arthritis patient treated with methotrexate

The immune response in canine and human leishmaniasis and how this influences the diagnosis- a review and assessment of recent research

Leishmaniasis is a widespread but still underdiagnosed parasitic disease that affects both humans and animals. There are at least 20 pathogenic species of Leishmania, most of them being zoonotic. The diagnosis of leishmaniasis remains a major challenge, with an important role being played by the species of parasites involved, the genetic background, the immunocompetence of the host. This paper brings to the fore the sensitivity of the balance in canine and human leishmaniasis and addresses the importance of the host's immune response in establishing a correct diagnosis, especially in certain cases of asymptomatic leishmaniasis, or in the situation the host is immunosuppressed or acquired leishmaniasis through vertical transmission. The methods considered as a reference in the diagnosis of leishmaniasis no longer present certainty, the diagnosis being influenced mostly by the immune response of the host, which differs according to the presence of other associated diseases or even according to the breed in dogs. Consequently, the diagnosis and surveillance of leishmaniasis cases remains an open topic, requiring new diagnostic methods adapted to the immunological state of the host.

Multifunctional, TNF-α and IFN-γ-Secreting CD4 and CD8 T Cells and CD8High T Cells Are Associated With the Cure of Human Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a chronic and often fatal disease caused by protozoans of the genus Leishmania that affects millions of people worldwide. Patients with symptomatic VL have an impaired anti-Leishmania-specific CD4⁺ T-cell response, which is reversed after clinical cure. In contrast, the quality of the CD4⁺ and CD8⁺ T-cell responses involved in resistance and/or cure of VL relies on the capability of these cells to activate polyfunctional and memory responses, which are associated with the simultaneous production of three cytokines: IFN-γ, IL-2, and TNF-α. Models for the development of CD4 and CD8 T-cell quality in memory and protection to leishmaniasis have been described previously. We aimed to assess the functionality of the T cells involved in the recovery of the immune suppression throughout the VL treatment. Therefore, we cultured peripheral blood mononuclear cells (PBMCs) from VL patients and healthy controls in vitro with soluble Leishmania antigen (SLA). Cell surface markers and intracellular cytokine production were determined on days 7, 14, 21, 30, 60, 90, and 180 after the beginning of chemotherapy. We observed that the frequencies of CD4⁺TNF-α⁺IFN-γ⁺ and the multifunctional CD4⁺IL-2⁺TNF-α⁺IFN-γ⁺, together with CD4⁺TNF-α⁺ and CD4⁺IFN-γ⁺ T cells, increased throughout and at the end of the treatment, respectively. In addition, enhanced frequencies of CD8⁺IL-2⁺TNF-α⁺IFN-γ⁺ and CD8⁺TNF-α⁺IFN-γ T cells were also relevant in the healing process. Noteworthy, the frequencies of the CD4⁺ and CD8 central-memory T cells, which produce IL-2, TNF-α, and IFN-γ and ensure the memory response against parasite reinfection, are significantly enhanced in cured patients. In addition, the subset of the non-functional CD8^Low population is predominant in VL untreated patients and decreases along the chemotherapy treatment. In contrast, a CD8^High subset increased towards the cure. Furthermore, the cure due to treatment with meglumine antimoniate or with liposomal amphotericin B was associated with the recovery of the T-cell immune responses. We described the evolution and participation of functional T cells during the treatment of patients with VL. Our results disclosed that the clinical improvement of patients is significantly associated with the participation of the CD4⁺ and CD8⁺ cytokine-secreting T cells.

Tinkering with targeting nucleotide signaling for control of intracellular Leishmania parasites

Nucleotides are one of the most primitive extracellular signalling molecules across all phyla and regulate a multitude of responses. The biological effects of extracellular nucleotides/sides are mediated via the specific purinergic receptors present on the cell surface. In mammalian system, adenine nucleotides are the predominant nucleotides found in the extracellular milieu and mediate a constellation of physiological functions. In the context of host-pathogen interaction, extracellular ATP is recognized as a danger signal and potentiates the release of pro-inflammatory mediators from activated immune cells, on the other hand, its breakdown product adenosine exerts potential anti-inflammatory and immunosuppressive actions. Therefore, it is increasingly apparent that the interplay between extracellular ATP/adenosine ratios has a significant role in coordinating the regulation of the immune system in health and diseases. Several pathogens express ectonucleotidases on their surface and exploit the purinergic signalling as one of the mechanisms to modulate the host immune response. Leishmania pathogens are one of the most successful intracellular pathogens which survive within host macrophages and manipulate protective Th1 response into disease promoting Th2 response. In this review, we discuss the regulation of extracellular ATP and adenosine levels, the role of ATP/adenosine counter signalling in regulating the inflammation and immune responses during infection and how Leishmania parasites exploit the purinergic signalling to manipulate host response. We also discuss the challenges and opportunities in targeting purinergic signalling and the future prospects.

Is Visceral Leishmaniasis Different in Immunocompromised Patients Without Human Immunodeficiency Virus? A Comparative, Multicenter Retrospective Cohort Analysis

Although visceral leishmaniasis (VL) can affect immunocompromised patients, data from the human immunodeficiency virus (HIV) infection context are limited, and the characteristics of VL in other immunosuppression scenarios are not well defined. A retrospective review of all cases of VL in immunocompromised patients from January 1997 to December 2014 in two Spanish hospitals on the Mediterranean coast was performed. We included 18 transplant recipients (kidney: 7, liver: 4, lung: 3, heart: 2, and blood marrow: 2), 12 patients with other causes of immunosuppression (myasthenia gravis: 3 and rheumatoid arthritis: 2), and 73 VL HIV-positive patients. Fever was more common in transplant patients (94.4%) and patients with other types of immunosuppression (100%) than in HIV-positive individuals (73.3%). Hepatomegaly was less common in transplant recipients (27.8%) and patients with other types of immunosuppression (41.7%) compared with HIV-positive patients (69.9%) (P = 0.01; P = 0.001, respectively). Patients with other types of immunosuppression had a median leukocyte count of 1.5 × 10⁹/L, significantly lower than HIV-positive patients (2.5 × 10⁹/L) (P = 0.04). Serology was more commonly positive in nontransplant immunosuppressed individuals (75%) and transplant recipients (78.6%) than in HIV-patients (13.8%) (P < 0.001). Antimonial therapy was rarely used in transplant recipients (1.9%) and never in patients with other immunosuppressive conditions, whereas 34.2% of HIV-positive patients received it (P = 0.05 and P = 0.01, respectively). Mortality was 16.7% in both transplant recipients and patients with other immunosuppressive conditions and 15.1% in HIV-positive patients. The features of VL may be different in immunosuppressed patients, with more fever and less hepatomegaly and leukopenia than in HIV-infected patients.

Visceral leishmaniasis in a patient with rheumatoid arthritis treated with methotrexate

A large number of complications have been associated with rheumatoid arthritis (RA), those of infectious etiology being of special relevance. Their high incidence is closely linked to the use of immunosuppressive medication. The spectrum of agents causing opportunistic infections in patients with RA is very broad; however, there are relatively few cases of Leishmania infection, especially in patients not being treated with biological drugs.

Visceral Leishmaniasis in a patient with rheumatoid arthritis undergoing treatment with methotrexate: Case report and review of the literature

There is growing concern regarding the emergence of visceral leishmaniasis (VL), a disseminated parasitic disease caused by protozoa of the genus Leishmania, as an opportunistic infection in immunocompromised patients. This association has been principally studied in the context of human immunodeficiency virus infection, but VL has also been reported in patients undergoing treatment with immunosuppressive medication for various indications. Here a case of VL in a patient with rheumatoid arthritis undergoing treatment with methotrexate and corticosteroid is presented. Despite the rarity of such incidents, physicians should include VL in the differential diagnosis because this infection, if left untreated, is characterized by significant mortality.

Visceral leishmaniasis and immunocompromise as a risk factor for the development of visceral leishmaniasis: a changing pattern at the hospital for tropical diseases, london

Visceral leishmaniasis (VL) is a parasitic protozoon infection caused by the Leishmania species and transmitted by sandflies. Patients acquire VL in five main tropical areas and the Mediterranean basin, and clinicians from non-endemic regions regularly see infected patients. We describe the population presenting with VL to the Hospital for Tropical Diseases (HTD), London and identify risk factors for developing VL.

An unusual case of anaemia in an octogenarian

Older patients referred for further investigation of anaemia are common in a geriatric medicine clinic and it is important to consider a wide range of underlying diagnoses. We present an unusual case of anaemia in an octogenarian in whom a diagnosis of visceral leishmaniasis was made. This is a rare and unusual diagnosis in this cohort of patients, especially within the UK; however, it is important to identify it, given its high mortality if left untreated. Our case, presumably contracted while in Andalucia, Spain, highlights the need for awareness in this group of patients, especially when travel within Europe is becoming commonplace.

Visceral leishmaniasis in immunosuppressed Caucasian patient

A 64-year-old man was admitted with fever, weight loss, fatigue and night sweats. He was known to have rheumatoid arthritis and had been taking methotrexate for 1 year. He had worked in Saudi Arabia until 1994 and had been living in Spain for 6 months every year. Clinical examination showed an enlarged spleen. Routine investigations showed pancytopaenia. Serial blood cultures were negative. CT scan confirmed splenomegaly and was otherwise unremarkable. Bone marrow biopsy revealed Leishmania amastigote consistent with a diagnosis of visceral leishmaniasis. After discussing with the hospital for tropical diseases (HTD), he was started on liposomal amphotericin B. Following two infusions of amphotericin B, he started improving as his fever, night sweats and weakness had settled. He was then discharged and followed up in HTD clinic 4 weeks later where he was found to be consistently improving.

Leishmaniasis, autoimmune rheumatic disease, and anti-tumor necrosis factor therapy, Europe

We report 2 cases of leishmaniasis in patients with autoimmune rheumatic diseases in Greece. To assess trends in leishmaniasis reporting in this patient population, we searched the literature for similar reports from Europe. Reports increased during 2004–2008, especially for patients treated with anti–tumor necrosis factor agents.